JP2000357301A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve exact recording and reproducing of data by specifying the gap width of magnetic heads for reading the recording data on a magnetic tape having guard bandless recorded digital signals, the width of the recording tracks on the magnetic tape, the maximum wavelength of the recording signals and main and adjacent track azimuth angles to specific relations. SOLUTION: The recording data of the magnetic tape guard bandless recorded with the digital signals by allowing the magnetic tape wound around a rotary drum provided with a plurality of magnetic heads varying in the azimuth angles to travel are read. The gap width of the magnetic heads of the this time is defined as Wg, N as a positive integer, Wt as the width of the recording tracks on the magnetic tape, λmax as the maximum wavelength of the recording signal and θ1 and θ2 as the main and adjacent track azimuth angles. In such a case, Wg=Wt+N/A±sin-1 (0.1πWtA)/πA, A=(tan|θ1|+ tan|θ2|)/θmax and Wg<=2 Wt are satisfied. As a result, the crosstalks from the adjacent tracks are decreased and the higher density recording is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating head type magnetic recording / reproducing apparatus, and more particularly, to a magnetic tape on which digital signals are recorded in a guard bandless manner using a plurality of magnetic heads having mutually different azimuth angles. When playing,
The present invention relates to a magnetic recording / reproducing apparatus capable of reducing crosstalk between adjacent tracks.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus using a magnetic tape as a magnetic recording medium, such as a VTR and a data recording / reproducing apparatus for a computer, for example, a rotary head device 1 as shown in FIG. 6 is used. . The rotating head device 1 includes a magnetic head 2a for recording and reproducing data at a predetermined azimuth angle θ ₁ and a magnetic head 2b for recording and reproducing data at a different azimuth angle θ ₂ . It is provided in the upper opposing position. Magnetic tape T
Runs helically around the rotary head device 1.

FIG. 7 shows scanning of a magnetic head from the recording surface side of a magnetic tape T in the apparatus shown in FIG. Since the magnetic tape T is helically wound around the rotary head device 1, the magnetic heads 2a and 2b scan the recording surface of the magnetic tape T obliquely.

At this time, first, recording is performed on the track a1 by the magnetic head 2a, and recording is performed on the track b1 adjacent to the track a1 by the magnetic head 2b. When the magnetic head 2a scans the magnetic tape T again, the track a adjacent to the track b1
2 is recorded. Hereinafter, data is recorded by the magnetic head 2a and the magnetic head 2b scanning the magnetic tape T alternately.

In order to increase the recording density, it is necessary to reduce the interval between tracks as much as possible. Currently home V
In TR, DAT, and the like, when data is recorded, the magnetic head 2b moves the track a recorded by the magnetic head 2a.
A method of overwriting a part of area 1 is adopted. With this method, so-called guard-bandless recording, in which the distance between tracks can be made zero, is performed.

According to the above method, the track width Wt of the recording track on the magnetic tape T on which the guard bandless recording is performed is _{expressed as} follows.
The magnetic head 2a, is shorter than the magnetic gap width W _g of 2b. Therefore, when playing a track on the magnetic tape T, the magnetic gap of the magnetic head 2a, 2b will be scanned in adjacent tracks _{W o (= Wg-W t} ) min protrusion while. This _Wo is called the off-track width.

[0007] In the guard band-less recording is read by a magnetic gap that protrudes off-track width W _o component, it is necessary to suppress the signal strength of the data recorded on adjacent tracks (crosstalk).

For this reason, a so-called azimuth recording method is adopted in which adjacent tracks are recorded by magnetic heads having different azimuth angles.

[0009] In Figure 7, the track a1, a2 is the azimuth angle is recorded by the magnetic gap 2a is theta _1, track b1 magnetic gap 2b is azimuth angle theta ₂
Recorded by

When reproducing a magnetic tape recorded by the azimuth recording method, a magnetic head for reproducing data reads only a signal from a track recorded by a magnetic head having the same azimuth angle as its own azimuth angle.

The magnetic gap of the magnetic head extends over adjacent tracks by the off-track width. However, since adjacent tracks are recorded by magnetic heads having different azimuth angles, crosstalk is suppressed by azimuth loss. For example, if the wavelength is 0.5
When reproducing a magnetic tape in which a signal of .about.2.0 .mu.m is recorded in a guard bandless format in a format of a track width of 15 .mu.m to 20 .mu.m, the ratio of the crosstalk output to the output from the reproduction target track (main track) is-. 20dB
It can be suppressed below.

The above-described magnetic recording / reproducing apparatus is of a two-head type. In addition, the azimuth recording method is also employed in a 4-head magnetic recording / reproducing apparatus.

[0013] Alternatively, there is a magnetic recording / reproducing apparatus of a type in which a plurality of magnetic heads in which a recording-only magnetic head and a reproduction-only magnetic head are combined are provided on a rotating drum. In this case, the azimuth angle of the magnetic head is
Corresponding one set of recording and reproducing heads is the same, and different sets of recording and reproducing heads are different.

[0014]

In recent years, in a data recording / reproducing apparatus for a VTR or a computer, the track width has been reduced so as to reduce the track width in order to realize high-density recording on a magnetic recording medium.

[0015] However, when advancing the narrow track, for track width W _t becomes smaller, the output from the main track is reduced. In addition, the off-track width W _o is also reduced by reducing the size of the magnetic head with the narrow track.
However, merely reducing the off-track width W _o does not reduce the crosstalk output. Therefore, the ratio of the output of the crosstalk to the output from the track to be reproduced increases.

In particular, when the track width _Wt is 10 μm or less, the ratio of the crosstalk output to the output from the main track often exceeds -20 dB, which hinders the accurate reproduction of the recorded data. I was

An object of the present invention is to solve the above-mentioned conventional problems, and it is possible to reduce the output of crosstalk and perform accurate recording and reproduction of data even when the track is narrowed. It is an object of the present invention to provide a magnetic recording / reproducing apparatus which can perform the above.

[0018]

A magnetic recording / reproducing apparatus according to the present invention comprises a rotating drum provided with a plurality of magnetic heads having different azimuth angles, and a traveling mechanism for traveling a magnetic tape wound around the rotating drum. In the magnetic recording / reproducing apparatus having the following, the gap width (the width of the magnetic gap with respect to the direction in which the magnetic tape is scanned) Wg of the magnetic head for reading the recording data of the magnetic tape on which the digital signal is recorded in the guard bandless manner is represented by the following _equation (5). And Equation 6 are set.

[0019]

(Equation 5)

[0020]

(Equation 6)

Where N is a positive integer, W_tIs magnetic tape
Track width of the upper recording track, λ_{m ax}Is the maximum of the recording signal.
Large wavelength, θ₁Is the main track azimuth angle, θ_TwoIs an adjacent tiger
3 shows the azimuth angle.

Reference is made to FIG. 1 to explain equation (5). 1A is a digital signal with a wavelength λ which are shown in FIG. 1B, the track width W _t, the track of the guard band-less recorded magnetic tape T1 (main track), by scanning the magnetic head gap width W _g FIG. In the magnetic head, only the magnetic gap G is shown. Track T1 are recorded by the azimuth angle theta ₁ of the magnetic head, track T2 adjacent to the track T1 is recorded by the azimuth angle theta ₂ of the magnetic head. A digital signal is recorded for one wavelength (= λ) in a section demarcated by diagonal lines drawn on each track.

As shown in FIG. 1A, the off-track portion of the magnetic gap G is located in a section defined by the diagonal lines A1 and A2 of the track T2, and the end a of the off-track portion
And the end b are on the oblique line A1 and the oblique line A2, respectively. At this time, by the off-track section,
The intensity (crosstalk) of the signal read from the track T2 becomes zero. That is, crosstalk is minimized.

Because the crosstalk is an integrated value of the signal strength at each point of the off-track portion, the off-track portion has a digital signal 1 between the end a and the end b.
Integrating the signal strength at each point in the off-track portion is equivalent to integrating one wavelength of the digital signal in FIG. 1B, and integrating one wavelength of the digital signal in FIG. This is because the value becomes 0.

If the off-track width at this time is W _o ,

(Equation 7) And hence

[0026]

(Equation 8) It is.

Further, when going to extend the length of the off-track portion, when the off-track width is a positive integer multiple of W _o, the ends a of the off-track portion to the left of the diagonal line A1 It is located on the drawn oblique line, and the crosstalk becomes zero.

For example, when the off-track width is twice as large as W _o , the end a of the off-track portion is located on the diagonal line A3 on the left side of the diagonal line A1. At this time, integrating the signal intensity at each point from the end a to the end b of the off-track portion is equivalent to integrating the two wavelengths of the digital signal in FIG. Is also 0.

Therefore, the condition of the off-track width W _o to minimize the crosstalk is as follows:

(Equation 9) Becomes

In digital recording, the wavelength of the recording signal is
It becomes an integral fraction of the maximum wavelength λ _max .

[0031] when the wavelength of the recording signal is the maximum wavelength lambda _max, the off-track width which crosstalk minimized W _o1
Then

(Equation 10) It is.

For example, if the off-track width that minimizes crosstalk when the recording wavelength is half the maximum wavelength λ _max is W _o2 ,

[0033]

[Equation 11]

Similarly, when the recording wavelength is equal to n of the maximum wavelength λ _max
When the off-track width that minimizes crosstalk when the ratio is one-half is W _on ,

[0035]

(Equation 12)

The recording wavelength, when it is 1 n of the maximum wavelength lambda _max, even if the off-track width to a positive integer multiple of W _on, crosstalk becomes zero. W _o1 = nW _on .

That is, the wavelength of the recording signal is the maximum wavelength λ _max
It can be seen that the off-track width W _o1 that minimizes the crosstalk when is the off-track width that minimizes the crosstalk due to recording signals of all wavelengths used for digital recording.

Therefore, the gap width W _{g of the} magnetic head
To

(Equation 13)

By doing so, it is possible to minimize crosstalk due to recording signals of all wavelengths used for digital recording.

Where W _g is

[Equation 14] May be allowed.

When the wavelength of the recording signal is the maximum wavelength _λmax , the output ratio of the crosstalk to the output from the main track can be calculated by Expression 15.

[0042]

(Equation 15)

If the output ratio of the crosstalk to the output from the main track is -20 dB or less, the signal recorded on the main track can be reliably reproduced.

Therefore, if Equation 15 ≦ −20, the output ratio of the crosstalk to the output from the main track is −
It can be less than 20 dB. That is, crosstalk can be reduced to a range where there is no practical problem.

By solving the equation 15 ≦ −20 for W _o ,

(Equation 16) Becomes

[0046] Incidentally, the above-described, the wavelength of the recording signal, when the maximum wavelength lambda _max, off-track width which crosstalk minimized

[Equation 17] Is the off-track width that minimizes Equation 15.

Further, the off-track portion must be made to extend beyond the track T2 in FIG. 1A and not reach the track T3. Track T3 is because it is recorded by the magnetic head having the same azimuth angle theta ₁ and the magnetic head for recording tracks T1, off-track portion, a signal recorded in the track T3 reaches the track T3,
Since the signal is almost completely read, the signal recorded on the track T1 cannot be accurately reproduced.

Therefore, in the present invention, the off-track width W _o must be smaller than W _t , and the magnetic gap width W _g of the magnetic head must be smaller than 2 W _t as shown in Equation 6.

The magnetic gap width W _g of the above-described magnetic head
Is effective when the off-track portion of the magnetic gap G is applied to only one of the tracks on both sides adjacent to the main track.

When the off-track portion of the magnetic gap G is applied to both tracks adjacent to the main track, it is necessary to calculate the off-track width W _o twice. Moreover, the off-track portion, so as not to exceed the track on both sides adjacent to the main track, the off-track width W _o, it should be less than or equal to 2W _t. Therefore, the magnetic gap width _Wg must be 3 _Wt or less.

That is, when the off-track portion of the magnetic gap G is applied to the tracks on both sides adjacent to the main track, the gap width W _g of the magnetic head is set so as to satisfy the following _equations (18) and (19). Set to.

[0052]

(Equation 18)

[0053]

[Equation 19]

Further, the magnetic recording / reproducing apparatus of the present invention has a magnetic drum having a rotating drum provided with a plurality of magnetic heads having different azimuth angles and a traveling mechanism for traveling a magnetic tape wound around the rotating drum. In the recording / reproducing apparatus, the gap width (width of the magnetic gap with respect to the scanning direction of the magnetic tape) W _g of the magnetic head for reading the recording data of the magnetic tape on which the digital signal is recorded in the guard bandless manner is expressed by the following _equations (20) and (21). It is characterized by being set to satisfy.

[0055]

(Equation 20)

[0056]

(Equation 21)

[0057] However, W _t is the track width of the recording track on the magnetic tape, lambda _min is the minimum wavelength, theta ₁ track for playback (main track) azimuth angle of the recording signal, theta ₂ represents an adjacent track azimuth angle ing.

In digital recording, a signal recorded on a magnetic tape represents bits of a digital signal.
The modulation is performed so that 0 or 1 does not continue more than a certain number, so that the wavelength of the recording signal is equal to or less than a certain maximum wavelength, for example, 8 used in DAT. The maximum wavelength λ _max of the recording signal modulated by the −10 modulation method is four times the minimum wavelength λ _min .
_max is hardly greater than four times the minimum wavelength λ _min .

Therefore, the magnetic gap width W _g is actually set by the equations (20) and (21), which are equations in which the digital magnetic recording / reproducing apparatus is obtained by replacing λ _max in equations (5) and (6) with 4λ _min. I don't care.

The method of determining the magnetic gap width Wg of the magnetic head according to _equations (20) and (21) is based on the case where the off-track portion of the magnetic gap G is applied to only one of the tracks on both sides adjacent to the main track. It is effective for

When the off-track portion of the magnetic gap G is applied to the adjacent tracks on both sides, the gap width Wg of the magnetic head is set so as to satisfy the following _equations (22) and (23).

[0062]

(Equation 22)

[0063]

(Equation 23)

The magnetic head comprises an MR type thin film magnetic head, an inductive head, and a protective layer formed of a magnetic or non-magnetic material laminated on a substrate formed of a magnetic or non-magnetic material. The magnetic gap of the MR type thin film magnetic head and the magnetic gap of the inductive head are sliding type thin film magnetic heads which are exposed on an end surface of the magnetic head which is a tape sliding surface. Is preferred.

In the present invention, it is necessary to form the magnetic gap width of the magnetic head with an accuracy of 0.1 to 0.2 μm. Conventionally, a magnetic head that has been often used as a magnetic head of a rotary head type magnetic recording / reproducing device has a core made of a magnetic material joined thereto, and the joining portion forms a magnetic gap, such as a MIG head or a laminated head. This is a so-called bulk type magnetic head. However, in the bulk type magnetic head, since the magnetic gap is formed by grinding the core, it is very difficult to form the magnetic gap with an accuracy of 0.1 to 0.2 μm.

The MR thin-film magnetic head is formed through the following steps. A magnetic material is laminated on a substrate made of a magnetic material or a nonmagnetic material by plating or sputtering, and a lower shield layer is patterned by photolithography. On the lower shield layer, a lower gap layer made of an insulating material, a magnetoresistive element, and an upper gap layer made of an insulating material layer,
Each of them is formed by laminating materials by sputtering and forming patterns by photolithography as necessary. A magnetic material is laminated on the upper gap by plating or sputtering, and an upper shield layer is patterned by photolithography.

The inductive head is formed through the following steps. An insulating layer serving as a gap layer is laminated on the lower core layer also serving as the upper shield layer of the MR type magnetic head by a sputtering method. A coil layer is formed by frame plating a conductive material on the insulating layer. A magnetic material is laminated on the coil layer via an insulating layer by plating, and the upper core layer is patterned by photolithography.

As described above, in the MR type thin film magnetic head and the inductive head, the magnetic gap is formed by photolithography. Therefore, 0.1-
It is easy to obtain a processing accuracy of 0.2 μm unit.

In particular, M
The R-type thin-film magnetic head can directly respond to a signal magnetic field at the time of data reproduction, so that the output can be a high reproduction output regardless of the speed of the magnetic tape. Further, since the inductance can be reduced, it is easy to cope with a higher frequency of the recording signal.

[0070]

FIG. 2 is a perspective view of a sliding thin-film magnetic head used in a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

The sliding type thin film magnetic head comprises an MR type thin film magnetic head 12 for reproduction, an inductive head 13 for recording, and a protective layer formed of alumina titanium carbide on a substrate 11 formed of alumina titanium carbide. 15 is formed by lamination.

The magnetic gap of the MR type thin-film magnetic head 12 and the magnetic gap of the inductive head 13 are exposed at the end face of the sliding type thin-film magnetic head which is to be the tape sliding surface. A current flowing through the MR thin-film magnetic head 12 and the inductive head 13 flows through the electrode 16. The MR thin-film magnetic head 12 and the inductive head 13 are covered with an insulating layer 14.

A plurality of sliding thin film magnetic heads as shown in FIG. 2 are installed on a rotating drum. For example, as shown in FIG. 6, two sliding thin-film magnetic heads 2a and 2b are mounted on a rotating drum 1a so as to face each other. At this time, the azimuth angle of the magnetic head is set by slidably mounting the thin-film magnetic head with respect to the rotating drum. In this embodiment, the azimuth angle of the sliding thin-film magnetic head 2a is θ ₁ , and the azimuth angle of the sliding thin-film magnetic head 2b is θ ₂ . The magnetic tape T runs while being helically wound around the rotary head device 1.

In the magnetic recording / reproducing apparatus of the present embodiment, data is recorded while the inductive head 13 scans the magnetic tape T of FIG. 6 obliquely. Also, at the time of recording, as in FIG. 7, guard bandless recording is performed by overwriting a part of the recording track.
Track width of the recording track is W _t.

Further, three or more sliding type thin film magnetic heads may be mounted on the rotating drum 1a.

The wavelength λ of the signal recorded on the magnetic tape
Is determined by the frequency f of the recording signal during recording and the tape running speed v. That is, λ = v / f.
For example, the tape traveling speed is v = 10 (m / s), and the frequency f of the recording signal is f = 5, 10, 15, 20 (MH
z), the wavelength λ of the recording signal on the magnetic tape is λ
= 2.0, 1.0, 0.7, 0.5 (μm).

FIG. 3 shows the M of the sliding type thin film magnetic head of FIG.
R-type thin film magnetic head 12 and inductive head 1
It is a partial enlarged front view of 3 periphery.

The MR thin-film magnetic head 12 has a lower shield layer 12a, a lower gap layer 12b, an MR element layer 12c, a hard bias layer 12d, an electrode layer 12e, an upper gap layer 12f, and a lower shield layer 12a, a lower gap layer 12b. And an upper shield layer 12g.

Inductive head 13 for writing provided on MR thin-film magnetic head 12 for reading
Is formed by laminating an insulating layer 13b, a coil layer 13c, an upper core layer 13d, and an insulating layer 14 on a lower core layer 13a also serving as an upper shield layer.

The lower gear of the MR thin-film magnetic head 12
Gap layer 12b, upper gap layer 12f, inductivity
The insulating layer 13b of the buhead 13 and the insulating layer 14
Al _TwoO_ThreeAnd SiO_TwoFormed by insulating materials such as
You. Also, a lower shield layer of the MR type thin film magnetic head 12
12a, upper shield layer 12g, inductive head
13, the lower core layer 13a and the upper core layer 13d
It is formed of a soft magnetic material such as permalloy.
The electrode layer 12e of the MR thin-film magnetic head 12
The coil layer 13c of the inductive head 13 is made of Cu.
It is formed of any conductive material. Furthermore, MR
The hard bias layer of the thin-film magnetic head is made of PtCo, etc.
Of hard magnetic material.

The lower shield layer 12a and the upper shield layer 1
The portion facing the recording medium sandwiched between 2g is MR
It becomes the magnetic gap Ga of the type thin film magnetic head 12. In addition, a portion of the insulating layer 13b which is a portion facing the recording medium sandwiched between the lower core layer 13a and the upper core layer 13d becomes a magnetic gap Gb of the inductive head 13.

The magnetic disk of the MR thin-film magnetic head 12
Cap width W_g1Are MR elements in contact with the upper gap layer 12f.
This is the width of the upper surface of the child layer 12c. In addition, inductive
Magnetic gap width W of the pad 13_g2Is equal to the width of the upper core layer
New In the present embodiment, W _g1= W_g2It is.

In the present embodiment, the magnetic gap width W _g1 of the MR thin-film magnetic head 12 is equal to
Is set to satisfy. Magnetic gap width W _g1
Is set so as to satisfy Equations (5) and (6) above, when the MR type thin-film magnetic head 12 scans a recording track on a magnetic tape to reproduce a recording signal, Reproduction (crosstalk) of a signal of a track adjacent to the track (main track) can be reduced to a level that causes no practical problem. That is,
The output ratio of the crosstalk to the output from the main track can be -20 dB or less.

For example, the track width W _t =
6 μm, and the main track azimuth angle θ ₁ = + 20
, The adjacent track azimuth angle θ ₂ = −20 °, and the maximum wavelength λ _max = 2.0 μm of the recording signal.

First, according to Equation 5, the MR type thin film magnetic head 1
The magnetic gap width W _g1 of

(Equation 24)

Further, according to Equation 6, the value of N is

(Equation 25)

Must be within the range. That is, N = 1 or 2.

That is, the magnetic gap width W_g1And W_g1=
8.75 ± 0.66 (μm) or W _g1= 11.50 ±
0.66μm), the output from the main track
The output ratio of crosstalk to -20 dB or less.
Can be

In this case, the tolerance of the magnetic gap width W _g1 must be kept within a range of ± 0.66 (μm). However, in a so-called bulk type magnetic head, such as a MIG head or a multilayer type head, which has been often used as a magnetic head of a rotary head type magnetic recording / reproducing apparatus, a magnetic gap is formed by grinding a core. It is very difficult to manufacture the magnetic gap width W _g1 with a tolerance within the range of ± 0.66 (μm).

The magnetic gap width W _g1 of the MR thin-film magnetic head 12 used in this embodiment is
2f is the width of the upper surface of the MR element layer 12c in contact with 2f.
The tolerance of the width of the upper surface of the MR element layer 12c is determined by the accuracy of patterning by photolithography. With the current technology, it is easy to make the patterning accuracy of photolithography approximately ± 0.1 to 0.2. Therefore, the magnetic gap width W _g1 is set to ± 0.6
It can be easily manufactured with a tolerance within the range of 6 (μm).

In the present embodiment, the magnetic gap width W _g1 of the MR thin-film magnetic head is set based on _Equations 5 and 6, but in this embodiment, the maximum wavelength λ _{max of the} recording signal is set. Is 2.0 μm, while the minimum wavelength λ _min of the recording signal is 0.5 μm. That is, λ _max =
Since in 4.lamda _min, the same results can be obtained by setting the basis of the magnetic gap width W _g1 of the number 20 and number 21.

FIG. 4 shows wavelengths of 2.0 μm, 1.0 μm,
A digital signal of 0.7 μm or 0.5 μm has a track width W _t = 6 μm and a main track azimuth angle θ ₁ = + 2.
A graph showing the relationship between the cross-track strength and the off-track width W _o of the magnetic gap of a reproducing magnetic head scanning a magnetic tape recorded at 0 ° and an adjacent track azimuth angle θ ₂ = -20 °. It is.

The abscissa indicates the off-track width, and the ordinate indicates the crosstalk output ratio with respect to the output from the main track.

FIG. 4 shows that the crosstalk intensity changes periodically with the change in the off-track width. Looking at the crosstalk of the recording signal having the maximum wavelength of 2.0 μm, the maximum value of the crosstalk is −17 dB.
It is.

If the strength of the crosstalk exceeds -20 dB, it will hinder accurate reproduction of the signal recorded on the magnetic tape. In other words, when the off-track width of the magnetic gap of the magnetic head is set arbitrarily, the crosstalk strength becomes −
The rate exceeding 20 dB becomes high, and it becomes impossible to reliably manufacture a magnetic head capable of accurately reproducing a signal recorded on a magnetic tape.

Further, it can be seen that crosstalk of a recording signal having a wavelength of 2.0 μm is minimized when the off-track width is an integral multiple of 2.75 μm. Further, the wavelength is 2.0 μm
Wavelengths of 1.0 μm, 0.7 μm,
It can be seen that the crosstalk of the 0.5 μm recording signal is also minimized when the off-track width is an integral multiple of 2.75 μm.

That is, the magnetic gap width W _g is _defined as W _g = W _t
+ W _o = 6.0 + N * 2.75 (μm) (N is a positive integer), the signal recorded on the magnetic tape
It can be seen that crosstalk can be minimized at all wavelengths.

Further, even if the off-track width has a tolerance of ± 0.66 (μm) before and after the point where the off-track width is an integral multiple of 2.75 μm, the crosstalk is -20 dB or less, which is a practical problem. It can be seen that it has been reduced to an insignificant degree.

Therefore, the magnetic gap width W _g1 is _defined as W _g1 =
6.0 + 1 * 2.75 ± 0.66 = 8.75 ± 0.66
(Μm) or W _g1 = 6.0 + 2 * 2.75 ± 0.66
It can be seen that setting = 11.50 ± 0.66 (μm) can reduce the crosstalk to a practically acceptable range.

The value of the magnetic gap width W _g1 is the same as the value derived from Equations 5 and 6 or Equations 20 and 21 described above.

FIG. 5 shows the wavelengths of 2.0 μm and 1.0 μm.
m, 0.7 μm, or 0.5 μm digital signal
Track width W _t = 6 μm, main track azimuth angle θ ₁ =
12 is a graph showing the relationship between the cross-track strength and the off-track width of the magnetic gap of the reproducing magnetic head scanning the magnetic tape recorded at + 10 ° and the adjacent track azimuth angle θ ₂ = -10 °.

The horizontal axis indicates the off-track width, and the vertical axis indicates the crosstalk output ratio with respect to the output from the main track.

5 and 4 differ in the azimuth angle of the magnetic head used for recording digital signals.

In FIG. 5, the maximum wavelength of 2.0
Looking at the crosstalk of the recording signal of μm, the maximum value of the crosstalk strength is −10 dB.

Therefore, when the off-track width of the magnetic gap of the magnetic head is arbitrarily set, the rate of crosstalk strength exceeding -20 dB is increased, and a magnetic head capable of accurately reproducing signals recorded on a magnetic tape is provided. Cannot be reliably manufactured.

Further, it can be seen that crosstalk of a recording signal having a wavelength of 2.0 μm is minimized when the off-track width is an integral multiple of 5.67 μm. Further, the wavelength is 2.0 μm
Wavelengths of 1.0 μm, 0.7 μm,
It can be seen that the crosstalk of the 0.5 μm recording signal is also minimized when the off-track width is an integral multiple of 5.67 μm.

That is, the magnetic gap width W _g is _defined as W _g = W _t
By setting + W _o = 6.0 + N * 5.67 (μm) (N is a positive integer), it can be seen that crosstalk can be minimized at all wavelengths of the signal recorded on the magnetic tape.

Further, even if the off-track width has a tolerance of ± 0.61 (μm) before and after the point where the off-track width becomes an integral multiple of 5.67 μm, the crosstalk is -20 dB or less, which is a practical problem. It can be seen that it has been reduced to an insignificant degree.

Therefore, the magnetic gap width W _g1 is calculated by the following equations (5) and (6) so that W _g1 = 6.0 + 1 * 5.67 ± 0.6.
1 = 11.67 ± 0.61 (μm) or W _g1 = 6.0
+ 2 * 5.67 ± 0.61 = 17.34 ± 0.61 (μ
m), it can be seen from this graph that the crosstalk can be reduced to -20 dB or less when the magnetic recording / reproducing apparatus is configured using the MR type thin film magnetic head set as follows.

Also, comparing the graph of FIG. 4 with the graph of FIG. 5, it can be seen that as the azimuth angle decreases, the crosstalk increases. However, according to the present invention, regardless of the magnitude of the azimuth angle, the crosstalk can be reliably reduced to −20 dB or less.

In the MR thin-film magnetic head according to the above-described embodiment of the present invention, the magnetic gap Ga is applied only to one of the tracks adjacent to the main track.
In the case where the off-track portion is used, the crosstalk is effectively reduced.

When the off-track portion of the magnetic gap Ga is applied to the tracks on both sides adjacent to the main track, the calculation needs to be performed by doubling the off-track width W _o . Further, the off-track width W is set so that the off-track portion does not exceed the tracks on both sides adjacent to the main track.
the _o, it is necessary to less than 2W _t. Therefore, it must be a magnetic gap width W _g smaller than 3W _t.

That is, when the off-track portion of the magnetic gap G is applied to the tracks on both sides adjacent to the main track, the gap width W _g of the magnetic head satisfies Expressions 18 and 19 as described above. Set to

For example, the track width W _t on the magnetic tape
= 6 μm and main track azimuth angle θ ₁ = + 20
°, the adjacent track azimuth angle θ ₂ = −20 °, and when the maximum wavelength of the recording signal is λ _max = 2.0 μm, the magnetic gap width W of the MR type thin film magnetic head 12 is first obtained from Expression (18). _g1

[0115]

(Equation 26)

Further, from the equation (19), the value of N is

[Equation 27]

It must be within the following range. That is, N = 1 or 2.

That is, the magnetic gap width W _g1 is set to W _g1 = 1.
1.50 ± 1.32 (μm) or W _g1 = 17.00 ±
When it is set to 1.32 (μm), the output ratio of crosstalk to the output from the main track can be set to −20 dB or less.

[0119]

As is evident from the foregoing description, the magnetic recording and reproducing apparatus of the present invention, by the gap width W _g of the magnetic head is set appropriately, reduce crosstalk from adjacent tracks in all frequency of the recording signal It becomes possible to do. Particularly, in order to realize high-density recording on a magnetic recording medium, crosstalk can be reduced even when the off-track width with respect to the track width is increased by narrowing the track. High-density home VTRs and computer data recording / reproducing devices can be easily manufactured.

[Brief description of the drawings]

FIG. 1A is a conceptual diagram showing a state in which a magnetic head used in a magnetic recording and reproducing apparatus of the present invention is reproducing a magnetic tape on which a digital signal is recorded. 3B is a conceptual diagram of a digital signal recorded on the magnetic tape shown in FIG.

FIG. 2 is a perspective view of a sliding thin-film magnetic head used in the embodiment of the present invention.

3 is a partially enlarged front view of an MR type thin film magnetic head and an inductive head peripheral portion of the sliding type thin film magnetic head of FIG. 2;

FIG. 4 is a graph showing the relationship between the off-track width of a magnetic gap of a reproducing magnetic head scanning a magnetic tape and the strength of crosstalk.

FIG. 5 is a graph showing the relationship between the off-track width of a magnetic gap of a reproducing magnetic head scanning a magnetic tape and the strength of crosstalk.

FIG. 6 is a plan view of a rotary head device used in the magnetic recording and reproducing device.

FIG. 7 is a diagram showing scanning of a magnetic head from the recording surface side of a magnetic tape T in the apparatus of FIG. 6;

[Explanation of symbols]

1 rotating head device 2a, 2b magnetic head Ga magnetic gap 11 substrate 12 MR thin-film magnetic head 13 inductive head 14 insulating layer 15 protective layer 16 electrode W _t track width W _g, W _g1 magnetic gap width W _o off track width

Claims (3)

[Claims] A plurality of magnetic heads having different azimuth angles;
A rotating drum provided with a
And a running mechanism for running the tightly attached magnetic tape.
In a magnetic recording / reproducing device, the digital signal
Reads recorded data on magnetic tape on which
Gap width of magnetic head (in the direction of scanning magnetic tape)
Width of magnetic gap) W_gIs the number 1 and the number
2. Magnetic recording characterized by satisfying (2) below.
Playback device. (Equation 1)(Equation 2)Where N is a positive integer, W_tIs the recording track on the magnetic tape.
Track width, λ_{m ax}Is the maximum wavelength of the recording signal, θ₁Is
Main track azimuth angle, θ_TwoIs the adjacent track azimuth
Shows the angle. 2. A plurality of magnetic heads having different azimuth angles.
A rotating drum provided with a
And a running mechanism for running the tightly attached magnetic tape.
In a magnetic recording / reproducing device, the digital signal
Reads recorded data on magnetic tape on which
Gap width of magnetic head (in the direction of scanning magnetic tape)
Width of magnetic gap) W_gIs the number 3 and the number
4. Magnetic recording characterized in that it is set to satisfy No. 4.
Playback device. (Equation 3)(Equation 4)Where N is a positive integer, W_tIs the recording track on the magnetic tape.
Track width, λ_{m in}Is the minimum wavelength of the recording signal, θ₁Is
Main track azimuth angle, θ_TwoIs the adjacent track azimuth
Shows the angle. 3. The magnetic head according to claim 1, wherein an MR type thin film magnetic head, an inductive head, and a protective layer formed of a magnetic material or a non-magnetic material are laminated on a substrate formed of a magnetic material or a non-magnetic material. The magnetic gap of the MR type thin film magnetic head and the magnetic gap of the inductive head are sliding type thin film magnetic heads which are exposed on an end surface of the magnetic head which is a tape sliding surface. The magnetic recording / reproducing apparatus according to claim 1.